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Environment

Eggshells could find use in ceramics production

By Ben Coxworth
February 27, 2014
Eggshells could find use in ceramics production
Don't throw those eggshells away – they could be made into ceramics (Photo: Shutterstock)
Don't throw those eggshells away – they could be made into ceramics (Photo: Shutterstock)
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Don't throw those eggshells away – they could be made into ceramics (Photo: Shutterstock)
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Don't throw those eggshells away – they could be made into ceramics (Photo: Shutterstock)

According to the US Department of Agriculture, every year approximately 455,000 tons (412,769 tonnes) of discarded eggshells must be transported and disposed of in the US alone. Now, however, scientists at the University of Aveiro in Portugal have developed a method of using such eggshell waste in the production of ceramic goods.

Although the specifics of the technology are still under wraps, it involves incorporating crushed eggshells into a ceramic slurry which is subsequently processed "according to a specific protocol that includes a 3-cycle cooking phase." Samples of porous pavement made from the slurry exhibit desirable qualities such as porosity and water absorption, and are overall considered to be of sufficient quality to meet industry standards.

Besides keeping eggshells out of landfills, the process could also allow ceramics manufacturers to save money – the calcium in the shells would be a lower-cost alternative to calcite, which is traditionally used in the production of ceramic items. Additionally, calcite must be mined, with all the environmental consequences that doing so entails.

What's more, businesses in the food industry supplying the shells could make money by selling them to the ceramics industry, instead of spending money on having them taken away and dumped.

The process has been tested in the lab, and the university's Technology Transfer Office is now seeking industry partners to help finance a large-scale pilot project. And should ceramics manufacturers not have a need for all of the world's eggshells, scientists in India are working on a method of using them for carbon sequestration.

Source: University of Aveiro

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EnvironmentRecyclingWasteEnvironmentally-friendlyCeramicsUniversity of Aveiro
7 comments
Ben Coxworth
Ben Coxworth
Based out of Edmonton, Canada, Ben Coxworth has been writing for New Atlas since 2009 and is presently Managing Editor for North America. An experienced freelance writer, he previously obtained an English BA from the University of Saskatchewan, then spent over 20 years working in various markets as a television reporter, producer and news videographer. Ben is particularly interested in scientific innovation, human-powered transportation, and the marine environment.

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7 comments
Slowburn
Whatever happened to composting?
Wombat56
I had some back yard chickens as a kid. Chickens need a source of dietary calcium in order to produce eggs and egg shells.
At the time this mainly came from shell grit, crushed pieces of sea shell, but we also used to feed them some of their own crushed up egg shells.
With some reprocessing, I can't see why the shell couldn't be feed back to the chickens, mixed into their pelletised feed.
Dragon_Elder
composting and feeding back to your chickens are both great options but this is an attempt to reclaim a much larger amount of calcium from the food industry that wouldn't have space for composting (urban environments) nor own their own chickens. Anything that is simple and possibly even profitable to existing industry is more likely to actually happen then just doing it because it's "green".
MQ
Note: if you feed chickens large chunks of raw egg shell they start eating their own eggs (looks and smells the same as food). If they are heat treated (cooked) and crushed and added to the "chook" food it isn't a problem
We used to use the egg eaters as roasters when I was a kid (they quickly lost their heads when they become "antisocial"/cannibalistic). Probably not an issue in the factory farming of chickens as the hen is separated from her egg as soon as it is laid.
I agree that most agricultural waste isn't actually waste (bagasse is another), the nutrients it contains either came from the soil, fossil fuels or mined at some remote location, it is far better to return the "waste" to the soil or food chain so that it can be reused, recycled, renewed.
To say that the food manufacturers don't have chickens to feed the eggs to is a blinkered thing to say, the food industry is a great big chain and the chicken feed producers should look at something like this as a resource (we aren't talking about collecting the eggshells from your garbage bin, I live in an (sub)urban environment and compost all of my green waste, including lawn clippings and there is no smell etc, sure not possible in high density housing.). The reality is, it is most likely more economical to mine the primary minerals, necessary to feed chickens (and other livestock) than to collect and process the eggshells from the custard and cake mix manufacturers to recycle it as chicken (or pig) feed. But that doesn't stop them adding; carcases, offal, feathers and miscellaneous abattoir waste to the meat meal, isn't this just another nutrient stream.
Robert in Vancouver
This is the type of activity enviro protesters should focus on - finding profitable ways to use waste materials and by-products.
But instead, they focus on shutting everything down and going back to the stone age. They call it re-wilding. I call it crazy.
Kevin Pezzi
Unless egg whites are very thoroughly cooked, a heat-labile protein in them called avidin will impair biotin absorption. That definitely occurs in humans, and I assume (as an MD, not a veterinarian) that it also occurs in chickens, too. Thus feeding chickens uncooked eggshells may trigger a biotin deficiency, but turning eggshells into ceramic products is an egg-cellent idea!
The Hoff
Robo, I figured you were taking an uneducated jab. So I looked it up. Rewilding is large-scale conservation aimed at restoring and protecting natural processes and core wilderness areas, providing connectivity between such areas, and protecting or reintroducing apex predators and keystone species. Rewilding projects may require ecological restoration, particularly to restore connectivity between fragmented protected areas, and reintroduction of predators where extirpated. I think you need a new source for information then your narrow radio station. And while your at it you could do something yourself to improve the world by focusing on - finding profitable ways to use waste materials and by-products.